Safety lock for pivoted seat backs



Nov. 17, 1964 T. A. DAVIS 3,157,433

SAFETY LOCK FOR PIVOTED SEAT BACKS Filed Oct. 15, 1962 Thomas H. De v sINV EN 1 OR.

United States Patent 3,157,433 SAFETY LOCK FGR FEVGTED SEAT BAKS ThomasA. Davis, 1735 SW. Prospect Brive,

Portland, Greg. Filed (Bet. 15, 1962, Ser. No. 238,342 Claims. (Cl.297379) passenger by the rigid front seat back of a four door sedan thusis not available, and the rear seat passenger may be catapulted into thedash board or windshield,

over the collapsed front seat back. If the front seat is occupied, theadditional weight of the front seat back, and

perhaps the weight of a rear seat passenger, can thrust the front seatpassenger forward and inflict serious injury.

Many locking devices have been proposed heretofore with the view towardeliminating the foregoing hazards.

'However, they have not been completely satisfactory,

primarily because of complicated and costly construction andinstallation.

Accordingly, it is the principal object of the present invention toprovide a safety lock for pivoted seat backs,

which lock is of extremely simplified construction for economicalmanufacture, is readily adaptable for use with all types of pivoted seatbacks, and is of rugged construction for long operating life with aminimum of maintenance. r

The foregoing and other objects and advantages of this invention willappear from the following detailed description, taken in connection withthe accompanying drawing in which: 7

FIG. 1 is a side elevation of a seat and pivoted seat back assemblyincorporating a safety lock embodying features of the present invention;

FIG. 2 is a fragmentary foreshortened sectional view taken along theline 22 in FIG. 1 and showing details of construction and arrangement ofparts of the safety lock in the locking position;

FIG. 3 is a fragmentary foreshortened sectional view, similar to FIG. 2,showing the safety lock in the release position;

FIG. 4 is a fragmentary sectional view taken along the line 4-4 in FIG.2; and

7 line 5-5 in FIG. 3.

In FIG. 1 the seat 10 is mounted securely upon a vehicle body by suchmeans as the mounting brackets 12. The seat may extend the full width ofthe vehicle, as'in the case of a conventional two door sedan, or it maybe of'the presently popular bucket type which accommodates a singlepassenger. In either case a pair of seat backs are disposed side by sideand mounted independently of each other by means of separate pivots.Each half of the full width seat thus is provided with its ownindependent seat back, much in the same manner as each bucket seat isprovided with its own seat'back.

A conventional pivot mounting for a seat back 14 is illustrated in FIGS.2 and 3. Laterally spaced pairs of brackets 16, 18 and 16', 18' projectupward from the seat 10 adjacent the lateral ends of the rear sidethereof, and the brackets of each pair receive freely between them thedownwardly projecting cooperating bracket 29, 20'

3,157,433 Patented Nov. 1-7, 1964 on the underside of the associatedseat back 14. The cooperating brackets are provided with axiallyregistering openings 22 for the reception of .a conventional pivot bolt(not shown).

In accordance with the present invention, the conventional pivot boltsare replaced by the locking mechanism now to be described. One of thepivot bolts is replaced by a shaft 24 which extends freely through thealigned openings 22 and the outer end of the shaft is provided with ahand knob 26 by which to manipulate it, as described in detailhereinafter. The shaft is provided intermediate its ends with a radiallyprojecting elongated key 28. The outer seat bracket 16 of the pair andthe adjacent back bracket 2% are provided with keyways 30 communicatingwith their respective openings 22 and positioned so that they are inalignment when the seat back is in erect position. tioned to freelyreceive the key. The inner seat bracket 18 preferably is not providedwith a similar keyway.

The inner conventional pivot bolt (not shown) is replaced by a shaft 32which extends freely through the aligned openings 22 in the brackets16',18, 20'. This shaft also is provided with a radially projectingelongated key 34 which is freely receivable in keyways 36 provided inthe outer seat bracket 16' of the pair and in the back bracket 20'. Theinner seat bracket 18' preferablyis not provided with a similar keyway;

rods 44 and joining turnbuckle 45. This arrangement affords adjustmentin the overall length of the connecting assembly to accommodatevariations in spacings between the laterally spaced sets of pivotbrackets.

Alternatively, the rods and turnbuckle assembly may be replaced by alength of flexible cord such as a cable or chain, which accommodatesinterconnection of spaced shafts which, by virtue of some seat designs,are not disposed in axial alignment.

In FIG. 2 of the drawings the seat back 14 is disposed in erectposition. The keyways 30, 36 thus are in alignment and the coil spring38 has surged the shafts 24, 32 inward so that the keys 28, 34 extendthrough the associated keyways and abut at their inner ends against theinner seat brackets 18, 18'. Accordingly, the seat back is securelylocked in the erect position.

When it is desired to release the seat back for forward tilting, forexample to facilitate passenger entrance to or exit from the rear seat,the knob 26 or 42 is moved outward to the position illustrated in FIG.3. Both shafts 24, 32 thus are moved outward, against the tension of thecoil spring 38, until the keys 28, 34 have been'retracted only from thekeyways 30, 36 in the back brackets 2t), 29'. The seat back then may betilted forward as indicated in FIG. 5.

It is to be noted from FIG. 3 that when the keys 28, 34 are fullyretracted from the keyways in the back brackets, the coil spring 33 isfully compressed, thereby providing a fixed abutment which preventsfurther retraction of the keys from the keyways in the outer seatbrackets 16, 16'.

With the seat back tilted, the inner ends of the keys 28, 34 abutslidably against the adjacent surface of the back brackets 20, 29',under the force of the coil spring 33. Accordingly, when the seat backis again raised to These keyways are proporerect position and thekeyways in the back brackets 20, 2t? become aligned with the keyways inthe seat brackets 16, 15', the spring will pull the shafts 24, 32 inwardautomatically to lock the seat back in the erect position.

. of, the seats.

Although it is preferred to provide the locking keys and'associatedkeyways for both shafts 24 and 32, for maximum security, it will be"apparent that one of the conventional pivot bolts may be retained andthat only the other conventional pivot' bolt need be replaced by thelocking shaft 42 and associated structure. If it is replaced by shaft2fv and associated structure, a spring 'is mounted on the inner endportion of the shaft and backed by a retainer, as will be apparent.

The hand'knobs located between adjacent seat backs may be ditlicult'tomanipulate, and therefore theyrnay be replaced'by conventional backingretainers for the spring 38, if desired. The hand knobs also may berepla'ced by electrically actuated solenoids for moving the shafts. I rv The locking assembly is such that each shaft 24, 32

requires cooperation of only a pair of brackets, one (16 or 16projecting from the seat and the other (20 or 20') projecting from theseat back. Thus, the brackets 18, 18' may beomitted, although theypreferably are included for adding strength and providing better guidingof the shafts.

- g the other bracket of each pair being mounted on the seat 7 back, andeach pair of pivot brackets having aligned tioned to freely receive thekey therein and the key being proportioned to extend into both of saidopenings when aligned,.resilient means engaging the shaft and. urgingthe key toward locking position extending into both of said keyopenings, and operator means on the shaft for moving the key tounlocking position removed from one of said key openings. I

2. In a seat assembly including a seat, a seat back, and

spaced pairs of pivot'brackets on the seat and seat back, one bracket ofeach pair being mounted on the seat and pivot openings therein adaptedto receive a pivot shaft forming the axis of pivotal movement of theseat back relative to the seat: the combination therewith of a safetylock for the. seat back, comprising two pivot shafts each extendingslidably through the pivot openings of one of said pairs of pivotbrackets, a locking key oneach shaft, each pair of pivot brackets havingkey openings therein arranged for. mutual alignment when the .seat

7 back is in erect position, the key openings being propor- It will beevident from the foregoing that the safety lock of the present inventionmay be installed upon existing automobiles with a minimum ofmodification. The only requirements are that the existing pivot bolts beremoved and that keyways 30, 36 be cut into the existing brackets 16,2!1and 16', 20' as previously described, to accommodate the'keys'ZS, 34.The keys and keyways may take any non-circular form desired. V i

It will be apparent tothose skilled in the art that vari- '-ouschanges'may be made in the details of construction describedhereinbefore without departing from the spirit of this invention and thescope of the appended claims. Having now described my invention andthe'manner V in Which it may be used, what Iclaim'as new and desire {tosecure by Letters Patent is:

l.'In a'seat' assembly includinga seat, a seat back,

and spaced pairs of pivotbrackets on the seat and seat back, one bracketof each pair being mounted on the seat and the other bracket of eachpair being mounted on the seat back, and each pair of pivot bracketshaving aligned pivot openings therein adapted to receive a pivot shaftforming the axis of pivotal movement of the seat back relative to theseat: the combination therewith of a safety lock for theseat back,comprising apivot shaft extending slidably'through the'pivo't openingsof at least one of said pairs of pivot'brackets, a'locking key on saidshaft, said pair of pivot brackets having key openings therein arrangedfor mutual alignment when the seat 'back is in erect position, the keyopeningsbeing propor- 2,145,987 Liptak l' f Feb. 7,1939

tioned to freely receive 'the associated key therein and the. keybeing'pr'oportioned to extend'into both of said openings when aligned,connector'means interconnecting the shafts for simultaneous movement,resilient means engaging one of the shafts and urging the keys toward 7locking position extending into both of their associated key openings,and operator means on one of the shafts for moving the keys to unlockingposition removed from one of their associated key openings; v

3. The combination'of claim 2 wherein the, connector means comprises alongitudinally adjustable rod assembly.

4. In a seat assembly including a seat, a seat back, and spaced pairs ofpivot brackets on the seat and seat back, one bracket of each pair beingmounted on the seat and'the other bracket of each pair being mounted onthe seat back, and each pair of pivot brackets having aligned pivotopenings therein adapted to receive a pivot shaft forming the axis ofpivotal movement of the'seat back relative to the seat: the combinationtherewith a safety lock for the seat back, comprising a pivotshaft-extend ing slidably through the pivot openings of at least one ofsaid pairs of pivot brackets for longitudinal adjustment between lockingand unlocking positions, locking means on the pivot shaft andassociated'pivot brackets arranged for mutual engagement in the lockingposition of the pivot shaft to secure the seat'back against pivotalmovement relative to the seat and for mutual disengagement ,in theunlocking position of the pivot shaft to release the seat back forpivotal movement relative to the seat,

' and operator means on the shaft formoving the latter..

" 5. The combination of clairn'4' wherein there 'is a pivot shaft andlocking means associated With'each pair 7 of pivot brackets, andtherezis included connector means interconnecting the pivot shafts for.simultaneous movemerit thereof between said locking and unlockingpositions. 5 I V a References Cited in the file of this patent UNITEDSTATES PATENTS 2,431,263 Lundgren Nov. 18, 1947 2,815,796 Lohanofl'. jDec. 10,1957,

4. IN A SEAT ASSEMBLY INCLUDING A SEAT, A SEAT BACK, AND SPACED PAIRS OFPIVOT BRACKETS ON THE SEAT AND SEAT BACK, ONE BRACKET OF EACH PAIR BEINGMOUNTED ON THE SEAT AND THE OTHER BRACKET OF EACH PAIR BEING MOUNTED ONTHE SEAT BACK, AND EACH PAIR OF PIVOT BRACKETS HAVING ALIGNED PIVOTOPENINGS THEREIN ADAPTED TO RECEIVE A PIVOT SHAFT FORMING THE AXIS OFPIVOTAL MOVEMENT OF THE SEAT BACK RELATIVE TO THE SEAT: THE COMBINATIONTHEREWITH A SAFETY LOCK FOR THE SEAT BACK, COMPRISING A PIVOT SHAFTEXTENDING SLIDABLY THROUGH THE PIVOT OPENINGS OF AT LEAST ONE OF SAIDPAIRS OF PIVOT BRACKETS FOR LONGITUDINAL ADJUSTMENT BETWEEN LOCKING ANDUNLOCKING POSITIONS, LOCKING MEANS ON THE PIVOT SHAFT AND ASSOCIATEDPIVOT BRACKETS ARRANGED FOR MUTUAL ENGAGEMENT IN THE LOCKING POSITION OFTHE PIVOT SHAFT TO SECURE THE SEAT BACK AGAINST PIVOTAL MOVEMENTRELATIVE TO THE SEAT AND FOR MUTUAL DISENGAGEMENT IN THE UNLOCKINGPOSITION OF THE PIVOT SHAFT TO RELEASE THE SEAT BACK FOR PIVOTALMOVEMENT RELATIVE TO THE SEAT, AND OPERATOR MEANS ON THE SHAFT FORMOVING THE LATTER.